The government's road- and house-building plans pose the greatest threat to the English countryside in 60 years, according to Sir Andrew Motion, president of the Campaign to Protect Rural England (CPRE) and former poet laureate.

In a speech on Thursday, Motion will deploy Larkin and Wordsworth in an outspoken attack on what he describes as the government's "needless smearing of concrete across our irreplaceable countryside in a misguided attempt to kick-start the economy". He will attack George Osborne, Nick Clegg, Eric Pickles and planning minister Nick Boles, who will attend the speech and who Motion dubs "Boles the Builder".

Last Friday, Boles announced that planning permission for a wide range of industrial and commercial developments would in future be decided at national, not local level, including factories, warehouses, quarries and hotels. "We are determined to help bring about new investment and jobs. Opening up the fast-track system will help get sustainable development underway sooner," he said. Boles has also said the need for new housing could mean building on "environmentally uninteresting" fields and in designated green belt areas.

Motion will tell the CPRE's annual general meeting: "Our countryside is in greater danger than it has even been in my lifetime – or yours. For the first time, I really believe the warning Philip Larkin gave us in his poem 'Going, going' will come true. The warning that a great wash of concrete and tyres will smother our green places, so 'that will be England gone'."

He will accuse Boles of denying the potential of brownfield sites and doing "great harm" by refusing to acknowledge the need for smaller, affordable homes in towns and cities ahead of "ranch-style homes in green places, which maximise developer's profits". Boles, he will say, "leapfrogs brownfield sites and lands with a bricky crunch in the open countryside".

Motion will also criticise Osborne: "The chancellor had insisted that tarmacking new roads across priceless landscapes like Combe Haven valley is the best way to achieve growth. Really? How about re-routing that money to repair the many existing roads that are presently falling to bits."

The deputy prime minister is guilty of a "willful act of sabotage" by suggesting new towns should be built on greenfield sites, Motion will say. The poet will initially praise Pickles, the communities and local government secretary, and who oversees planning policy, for his pledge to protect green belts, before stating that "the reality that has flowed from this rhetoric is often so disappointing". CPRE estimates there are plans for 80,000 new houses on green belt land.

Motion will argue that green spaces are a fundamental human need: "Inside us all, wherever we live, is an absolutely primal atavistic need for green places and open spaces." In 2011, a government study concluded that looking after the UK's green spaces better was worth at least £30bn a year in health and welfare benefits.

"The damage to our home will be irreversible. The damage to us will be irreversible," Motion will say. "Lives cannot suddenly be made whole, if they never knew, [quoting Wordsworth], 'a sense of something far more deeply interfused, whose dwelling is the light of setting suns, and the round ocean, and the living air, and the blue sky'."

Motion will conclude by calling for "a return to a planning system which is truly democratic, prioritises brownfield development, and delivers genuinely affordable housing where it is needed."